I got Coded Arms a few days after it was released and have been playing it a lot lately. It is not the greatest FPS game in the world, but it is entertaining. The game is a fun FPS romp though a Matrix-like environment. The basis for the game is that people can now jack into computers and there are a bunch of elite hackers who have been trying (and dying) to break into a military computer.
Not much of a story, and it does not get developed at all in the game, but it's enough to setup the game and its environment. Remember the good ole days of DOOM and DOOM II? Where there was a skeleton story ("Marine on Mars") and then the game was basically shoot 'em up from point A to point B? That's what Coded Arms is. Don't expect a Halo or Half-Life type story here. If you can live with that, then you'll like Coded Arms.
The controls are a bit hard to get used to since the PSP only has one analog controller. I have the four face buttons mapped like a second analog controller, but it is still difficult to get used to. Thank goodness there is a decent auto-aim setting to help out (it can be turned off).
The graphics are pretty nice for a PSP game. The only thing is that the game uses the gimmick of "randomly generated levels" so that no level is the same for any player. That's all fine and dandy except for all levels now look like a mash of boxes. You go from one box to another shooting enemies and that is about it. There is no creative level design here because the system only knows how to randomly shove boxes together to form hallways and rooms. So most of the environments look like the same: drab grey and brown rooms.
The enemies are the silly kind from DOOM and Duke Nukem (remember that game?). Their AI teaches them three things: Run towards you, shoot at you and occasionally jump to "avoid" your shots. Not the smartest AI in the world -- especially given the premise of the game. They make up for the stupid AI with sheer number of enemies though.
There is not much motivation to move from level to level, at least storywise. But, they add files that can be collected in each level. The files amount to getting new weapons, weapon upgrades, or permanent health upgrades. This does make for motivation to complete levels as I want to get the better weapons and also to upgrade my current ones. If that is enough for you to play through the game, I don't know. I can't wait to get the lightning gun though!
There is a multiplayer portion to Coded Arms. But, since my wife does not do FPSs and she does not have a copy of Coded Arms, I have not yet been able to try the multiplayer aspect.
Overall, the game is pretty entertaining, I can't wait to get the bigger and better weapons. The game may not be for everyone because of the lack of story and the difficult controls.